Rock drill



i Patented Oct. 27, 1.9.31 l

MERVIN QESPATENT OFFICE dnurrivmn, or Aoramairoiv'r, New HAMPSHIRE, AssIGNoR 'ro sULLrvAN f i l Macnmnnv COMPANY, A consommer: or MASSACHUSETTS l Rooi: DRILL l Application alea 'ianuay 7,1925. serials-nwo. 245.174.

Y This invention'relates to rock drills, and more particularlyto a holey blowingdevice for fluid actuated rock drills of the hammer type 5 AAn object .of this 4invention is to provide an improved holeblowing device for fa, rock drill. Another object is r4to provide 'an improved hole blowing device `for. iiuid actuatedrockdrills of the `hammer type whereby l0 the fluid distribution valve may be held immovable tol effect ahole blowing operation. Stillanother objectv of this invention is to provide anfimproved hole yblowing device for a rock drill whereby the yfluid distributionv i5 valve may be'pneumatically 'shifted and held immovable toeffect a hole blowing operation.

- Still another objectofthis invention `is to.

1 provide an improved holefblowing device 'for Y a rock drill,.the device including a combined 2@ buffer plug and pistonmember actuated by pressure fluid for pneumatically shifting and holding the valve immovable to effect a hole blowing operation. f Yetanother object is to provide an improved 'hole'A blowing'y device 5 wherein a combined bufferplug and piston.

member isprovided-for shifting and holding the iiuid distributionkvalve immovable to effeet a hole blowing operation, and valve controlledmeans for 'controlling movement of 3Q the combined bufferplugand piston member. These and other objects of this invention'will howeverl subsequently vmore fully Y appear as the description proceeds. l Y f VIn the accompanying drawings, .there is l5 shown for purposes 'of illustration one form which the'invention may assume-in practice.

r i In these drawings,-

Fig. l :is a central'longitudinally entend'- ing,v vertical sectionalfvew through. a rock 13 drill with which the improved hole blowing' device is incorporated, the parts being shown -in position'to effect a hole' blowing operation. Fig. 2 is a view similar to F ig.l 1 with the parts shown in a different position; 1

- Fig: 3 is a fragmentary transverse sectional view taken substantially lon line 3-13 of Fig. 1 is aside elevational'view of the automatic Huid distributing valve.

V53 In the illustrative embodiment yof the intrated, the rear end ofthe cylinder'bore 2 is f lvention there is shown a rock drill ofthe pressure Huid actuated percus'sive typey comprising a cylinder 1 having a bore 2 in which a hammer piston `3 is mounted for reciprocable movement. The hammer piston`3 is provided with aiforwardly projecting striking barstt reciprocably mounted within a bore 5 formedwithin a usual front cylinder head or buffer ring 6. The striking bar 4 is adaptedto impart a series of blows on the shank of a hollow drill steel 7 loosely mounted in 'a usual manner within'a chuck bushing 8s'ef cured to a chuck vsleeve 9 rotatably mounted within a usual chuck housing 10. Asillus'- vclosedby a suitable washer 1,1 while interposed between this'washer and av rear head member 12'is'a usual ratchet ring 13. As is usual Vin rock drills kofthe type disclosed, the chuck housing 10, the f ront cylinder Ahead 6, cylinder 1, rear washer 1.1, and rear head12,

and'theratchet ring 13 are maintained in assembled relation by-'sideirodslor bolts (not -shown).. f f LDrill lsteek-'rotation mechanism operated 75 by the hammer piston 3 is provided and this rotation` mechanism comprises a spirally grooved'frifle bar 14; extending forwardly through the washer 11 into engagement with the hammer piston 3 in the usual manner. @o

During the forward stroke of the hammer` piston, the riflebar freely rotates, thereby permitting freemovement of the hammer piston during the working stroke.v Upon the return strokeof the piston the rifle bar is held stationary'byv the usual ratchet and pawl' mechanism generally designated 15, and as a 'result the piston is slightly rotated. Rotary movement of the piston 3' is transmitted to M the drill steel 7 by ymeans offstraight flutes 90 16 formed on Athe periphery of the striking bar 4. The flutes 16 engage straightlugs 17 formed on a usual chuck nut 18 threadedly connected to lthe rotatable chuck sleeve 9. N From theforegoing it is evident that the drill @5 vsteel f7 is intermittently rotated during reciprocation of the hammer piston.

' Projecting'laterally from the cylinder` 1 is a valve chest 19 rhaving a bore 20. Suitably positioned within the bore 20 are oppo- 100 fl, its .inoperative positionbymeans of `afoiled having bores 23 and24of different diameter.-

i Reciprocably mounted within the bores 23,24L

is an automatic fluiddistributing jvalvef 2 5,

This `fluid distributing'valve may beo't an Asuitable'ftypev as the invention is not depen entuponthe particular'valve illustrated for il; its successful functioning andthefinventionj Y. may be Vused in connection with anyjtype-Q Y 10 pressure fluid tothefcylinder and exhaust ot valve 'which `lcontrols 'both thev admission of pressure kfluid theretromj.` The'valve 2 5fin i this instance is of. the `well-known three-spool 'diierentialtypehavingan,enlarged'centralj lfspool 26 and .end spools 27, the'spools 26, 27

' V having asldinglit with thebores' 2.4,; 235m! s ectivelyf 'Hereinthe central-spoot 2 6 of j *lj the vvalvecontrols .the admission of .pressure V-fluid'through an inlet28-toathefbore 124 and the:en djs'pools v27ftcontrfol freeexhaustports;

'f 29fand 30 respectivelyleading tromthe bores 233130 atmosphere; Theend'fspools 27 have. A Ywhen thedistribution valve25 ism the posiopposed actuating faces againstwhichpresn sure.fluid'mavv act for eiecting moveinent of' j. 25the distribution valve Vtr'omone 'extremepo- Af sitionto theother`Movement of the-'valve within-the valvelsleevef22 and which herein Y eonstitutesjapartot-themprovedf hole blowi-y ingdevieeas will laterbe described... .'Presif sure; fluid admittedy intozthebore 2190i Athe Valveychamberr may-pass to the rearward and Y Vfront ends 'of thecylinder Abore-2to edect `re- 1 f ciprocation ot,thehan'lmer"piston'throughJV ,fusual supplyzpassages; and 34'respeotively..

In thisV instance' the supply. passages 34 Vvalso serve as'exhaust passages frexhaustingf;

' y:thepressure"fluid from the oylindeni 25 in one direction is limited .byfa butfer'plug Blrigidly securedtoy thevalve sleeve 2l while movement ot thelfvalve inithelo'ppositedirec- 1 strike A an f unimpeded blow V oir the drillV steel 7 The exhaust fluid fromfthe forward end Y ott-he lc5`liii`derY bore .flows .through the pas- Lsage St'past the rear surtaceot'the trout end Y spool .'.27 Y cti-theadistribution; valve' and 0o .phere f VThe distributionfvalve'isheld in its tion iszliinited by"` a'loutl'erf1 plug 32.V carried t As is usual. inf rock ldrills@employingl the Y type-jotvalve"hereinidisclosedfpiston con- Oued l/hl'owin'g passages areV provided Pforadmitting pressureV -tluidv from Vthe cylinder Yto act against the opposed-actuating faces at v--th'e Vends of the valve.- 'SuchLthroWing pas,-

-sages may. be crossed as in thepresent` 4in'-v stanceinwhich athrowingp assagez leadsv fromthefrontendotthe cylinder'bore lto the Vand isoontro'lledby'` the hammer pistonf; STA

thepvalve' 25.'

Therimprova here biasing aeireeng'inj:

cludes a ,-reciprocable plunger-valve '37fslidablymounted in aboree38 formed within the .Valve sleeve .22, this plunger" valve being proided'i-2vith a'push button or other suitableopf erating elementf39', and :being Lgroovedfat 4()A 'intermediate V its ends; r As `illustrated,,fthe

Aplu'iigerfrval ve '37 is Vnormallyv maintained in passage 47Y stelvpositionedvalve sleeves21and 22, each spring 41 interposed between thebottom ot Y the borejandf'the lower end ofthe valve,

.movement of 'the plunger..valve within the "'iborebeinglimitedby a pinandfslot conneo-r tion '4:2'.`v` Thebore at ,thelowerend othe Valve is 'vented Vto atmospherekthrough a illustrative embodiment of the invention, the valve sleeve 22. has formedth'ereinfln arial member. Bressure-flud isV adapted tobe admitted to'v the bore 44 at the `forward side of Y'the membfer'32 through af passage 45 (see Fig.

'-.iestrictedport 43. Inl aecordancewith vthis 3)?connecting'the'pressure-iiuid inlet 28'with thezbore 38 andthe piort t6V connecting the borer38 rwiththe bore44; As shown, the bore 38 is'eonnected to atmosphere Vthrough :a vent in the normal. opstaan' fthe 14001;. aan, f

Vtion shown in Fig; 2lpr`essure luid'liows through inlet passage-28,`pastthe rearsnr- Y throughthe 5 exhaust passageg vto f atmos# forwardr position by vreason' ot. the `larger v.ettectiv e area,-o. the central spool'; and 'f by thee/prossime; actingoni 4the -rearend spool.

'YWhenf the -vhammer ijgiiston; uncovers/the throwing passage 36, pressure-:fluid is `admitted from the rearend ot the cylinder bore tothe forwardpend ofthe valve 25 and consequently 'theflatter is thrown rearwardlyY yto the position Ashown in Fig-l. Pressure fluid v'now enters'the forward end otf'gthecylinder borethrough inlet passageA 2,8 pastj the for- Y ward'surface'of theV central lspool 26. on the valve and through the passage-34: andfconsequently the hammer'piston f is .moved rrear- V v va'rfdly. ,I Exhaust 'now takes V.place through passagey 33j past-the fo'rii'ardr surfacegoffthe rear V spool '27 'of kthe distribution valveV and :through they exhaust passage v29` to atmos- I'Jhere.k Asrsoon asthe piston hasuneoveredthe throw/ii 1gpassage,35,y the distribu- Y tion valve 125. isfagain 'shifted to Vits l forward position and p this cycle 'of events continues during thenormal operationof thedrill.,

i Then itis desired .t0 effect avhole blowing operation, the operator presseshi'sthumb or viingervagainst the zpush button- 39 and'depresses'the plungergvalveB, movingthe 'latter'from theposition shown, inrrFig. 2'tothe position shown'in 'Fig-1,; fWhen the .plunger lvalve is in the position shown in Fig. l,

the groove 40 connects the passage 45 with the port 46 andconsequently pressure fluid,

area of the valve to the position shown in l Fig. 1 and holding the same immovable against the rear vbuffer plug 3l. .Pressure `fluid is then admitted from the inlet 28 'past the forward surface of the central spool 26 'of the distribution valve and through the passage 34 to the forward end of the cylinder bore 2. The continuous supplyof pressure fluid flowing tothis end ofthe cylinder bore forces the hammer piston 3 rearwardly against the rear cylinder washer ll and consequently the pressure flows from the cyl- I' inder bore through the flutes -16 on the striking bar 4, through the chuck nut l18 and thence through the bore in the drill steel 7 to the bottomrof the drill hole. Upon release of the push button 39, the plunger valve 37 is automatically returned to its inoperative pov `sition bythe spring 41 as shown in Fig. 2,

' a valvek buffer.

thereby cutting off' communication between. the passage 45 and the port 46 and connecting the latter with the port 47 and as a result the e bore44 at the forward endV of the member 32 is vented to atmosphere. The pressure fluid flowing from the cylinder bore through throwing passageV 36 maintains the piston member 32in itseXtreme rearward position as shown in Fig. 2 where it will then actas The distribution valve 25 will then resume its normal operation-and the drill will againk function in` a normal manner. These and other uses and advan- Y tages of this invention will be clearly apparent to those skilled in this art.

VWhile I have in this application specifically described one form which this invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration and that the invention Vrelative position of said piston with respect to said cylinder to conduct fluid to a hollow drill steel to blow the hole, a valve chest having a chamber and a fluid distributing valve i in said4 chamber controlling both the supply and exhaust for said cylinder, valve throwing passages between the opposed spaces in the valve chest chamber at the ends of the distributing valve andthe cylinder bore for supplying pressure fluid for actuating said valve, and a hole blowing deviceincluding a iuid actuated plunger projecting in the valve chest chamber at one end of said valve and normally constituting a stop for the l valve, said plunger also forming an end wall tuate saidfplunger, said plunger being movable to effect shifting of the fluid distributing valve against the resisting throwing pressure and for holding said distributing valve immovable in a position to maintain the piston ina position to effect a hole blowing operation.

2. In -a fluid actuated rock drill of the hammer type, the combination of a cylinder having a bore and a piston reciprocable therein,`means operative in a predetermined relaive position of said piston with respect to said cylinder to conduct fluid to a hollow drill steel to blow the hole, a valve chest and a fluid distributing valve therein controlling both the supply and exhaust of pressure fluid for said cylinder, buffer plugs for li-miting movement of said valve in opposite direc-tions, one of said buffer plugs being mounted for reciprocable movement in said valve chest, valve throwing passage between opposed spaces in the valve chest at the ends of said distributing valve and the device comprising means forv admitting pres- --J sure fluid to act on one end of said reciprocable buffer plug for effecting movement of the latter to shift the distributing valve against the resisting throwing pressure and for holding said distributing valve immovable against the other buffer plug to effect a hole blowing operation.

3. In a Huid actuated drill of the hammer type, the combination of a cylinder, a hammer piston, means operative in a predetermined relative position of said cylinder and piston to conduct cleansing fluid to a hollow steel to blow a hole, fluid supply and exhaust means for said cylinder including a distributing valve operative in a predetermined position thereof to bring said piston -to the predetermined relative position for hole blowing and there to maintainl it, and means for bringing said distributing valve to such position and 'holding it there including a fluid actuatedv element normally constituting a buffer to limit valve movement but movable under fluid pressure to move and hold the distributing valve and operator controlled valve means controlling fluid L supply relative to said fluid actuated element. In testimony whereof I aflix my signature.

MERVIN C. HUFFMA'N. 

